Is there a way to merge multiple identical materials
Have you tried this ...


Create a box object and apply a materials to it.
Select all the other mesh object that has multiple materials you don't want in your scene.
Select the newly created box object last. (Important select the box last)
Hit CtrlL, select material from the drop down list.
All your meshes should have the newly created box's material.
Save your file, Close it and reopen it to refresh the data cache.
Export the file to any appropriate format you may need.